Since 2009, Luis CdeBaca, the U.S. State Department's ambassador-at-large for human trafficking, has been an advocate for trafficking victims worldwide. CdeBaca oversees the State Department's annual reports on all countries' efforts to address modern slavery. He visited Houston this week to speak at Rice University and sat down with the Chronicle for an interview.

Q: Are the cantina-based sex-trafficking rings we've seen in federal cases in Houston unique to this region?

A: These aren't as common elsewhere. Tlaxcala, Mexico- based human slavery rings were historically the suppliers of prostitutes to Mexico City - then they began to export in the last decade. "We saw them here (in Houston cantinas) first and then they popped up in New York as flat-out prostitution."

In Houston, sex trafficking is often "masked by Central American cantina culture. … Along with the hierarchical organized crime groups, there are individual opportunists."

Q: Is Houston truly a hub for human trafficking?

A: Houston is home to a human-trafficking task force that's considered a model for the rest of the country. "You're finding more cases in Houston because you've got more watchmen on the watchtower …"

"Houston is one of the major cities of the world and (human trafficking arrives here) not because it is a transit point, but because people from all over the world come to work in Houston. … Because Houston is a destination city, it's a place where exploitation happens."

"I don't want cities to get into a back-patting contest: 'We're the worst.' "

Q: Recently, teen trafficking victims in Houston were awarded $600,000 from the sale of bars and properties linked to a trafficking ring. But the judge awarded money only to teenagers and excluded older victims.

A: "It will change the lives of the girls who are able to get some money from the sale of that cantina … but the reality of human trafficking is rarely as cut-and-dried as the judge and all of us would have preferred … Was she the girlfriend to a suspect? Had she done (prostitution) willingly previously?

"If they're enslaved, it doesn't matter if somebody was a prostitute before or whether somebody is a 'deserving victim' or not."

Q: How common is restitution for trafficking victims worldwide?

A: "In many ways, the work we're doing in the U.S. is driving international discourse."

CdeBaca has been working with the Brazilian government to push it to use confiscation laws to seize assets of plantation workers caught using slaves. Instead, owners pay relatively small fines.

"If you're going to call it slavery - otherwise you're demeaning the term - slavery should be handled the same level as extortion, kidnapping or as rape, the highest level of crime that's not homicide."